by a feedback Proportional-Integral-Derivative controller. The target hydrogen sulphide concentration (0.01%v/v) was achieved in 4.0–5.5 h. The micro-oxygenation level reached was considered to be the optimum in the short-medium term, since it kept the removal efficiency above 99% and minimised the oxygen concentration in the biogas during the days following the controller application. Specifically, the average biogas oxygen content was 0.09%v/v. Subsequently, biogas production was used as the parameter to regulate the oxygen supply.